An MRI (Magnetic Resonance Imaging) apparatus which receives magnetic resonance signals coming from a test object by means of an RF coil unit formed by a plurality of coil elements is ordinarily known. As the MRI apparatus of this type performs a process for reconfiguring an image or image processing by using magnetic resonance signals received by the respective coil elements simultaneously in parallel, it is necessary that electric and magnetic interference caused among the respective coil elements be excluded as much as possible. That is, a decoupling technology for excluding couplings caused among the respective coil elements is important.
A method for overlapping adjacent coil elements is an effective way of decoupling the respective coil elements. Further, a technology for providing each of a pair of coil elements with a sub-loop for decoupling in addition to a main loop and for overlapping the sub-loops of the pair of coil elements is known as a method for decoupling a pair of coil elements located not adjacent to and apart from each other (as disclosed, e.g., in Japanese Unexamined Patent Publication No. 2008-264497).
Meanwhile, a flexible RF coil unit which can be bent and can veil a portion of a test object is being studied. Such an RF coil unit may include coil elements to be put apart from each other if the RF coil unit is being open and flat but put close in space to each other if the RF coil unit is bent in some cases. It is difficult to exclude possibility that all the coil elements of this kind of flexible RF coil unit are cross-coupled with one another.
The technology disclosed by Japanese Unexamined Patent Publication No. 2008-264497 is to decouple a particular pair included in the plural coil elements which form the RF coil unit, and coil elements which can be decoupled are limited.
Thus, an RF coil unit of higher decoupling performance and an MRI apparatus having such an RF coil unit are desired.